JPS6345365A - Method and apparatus for reactive vapor deposition of substrate - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a vapor flow directed to a substrate in the form of an electrical electrode positively biased with respect to ground, in an atmosphere consisting of a reactive gas. The present invention relates to a method for reactively depositing metal compounds onto a substrate by evaporating at least one metal using an electron beam at pressures of up to 10" mIJ bar.

The metals used here are preferably those which give rise to so-called hard materials, such as titanium, zirconium, tantalum, vanadium and hafnium. Examples of hard substances include compounds of at least one of the metals and nitrogen (nitrides), compounds of carbon (carbides), and compounds of carbon and nitrogen (so-called carbide compounds). However, the method is also suitable for reactive vapors of other metals which react with oxygen to form oxides, for example.

Methods of the above type are described in J. vac. Sci. Tech.
nol,.

Band 9, No. 6. From November 1972
Bunsh published in December, pages 1385-1388
ah and I'1. ``Activat Reactive Deposition Methods for High Rate Deposition of Compounds'' by M. Aghuram.
ed Reac-tive EvaporationP
rocess for High Rate Depos
In the method described in that document, the metal is evaporated directly in a vacuum chamber by means of an electron beam at a relatively low accelerating voltage (10 KV). There is a linear electrode, which is positively biased with respect to earth, e.g. 80-200 V. When the device is in operation; While the positive electrode also serves as an electron donor, the positive electrode attracts negative charge carriers, which have a higher probability of ionization than 4C and are directly surrounded by the glow discharge.However, as is known The method and apparatus are of limited use on a laboratory scale, since the evaporation rate cannot be increased to the extent desired for industrial processes.The beam current and thus the beam efficiency cannot be increased. All experiments to increase the rate of evaporation by evaporation have been unsuccessful in that the reaction no longer proceeds stoichiometrically, even when a nozzle dedicated to the supply of reactive gases has been opened just above the evaporation zone. .The deposition rate is certainly locally 4-9.
7 μ7 n/min, however, cannot be distributed over large areas and the deposited layer contains a significant proportion of metal components that did not take part in the reaction.

Therefore, for coating production materials with hard materials on an industrial scale, almost exclusively the method of cathode sputtering with the aid of a magnetic field has been used. However, in this case about 1
A deposition rate of ~1.5 μ7 rt/min is not exceeded, or at least cannot be exceeded in a practical manner.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to develop a process of the type described at the outset, which simultaneously provides high deposition rates and at the same time stoichiometrically reacted components of metal and gas, and which is industrially possible. The objective was to improve it sufficiently so that it could be carried out on a commercial scale and at the same time under stable operating conditions.

Means for solving the problem (part 2) The problem is solved according to the invention in a method of the type mentioned at the outset, by: a) forming a metal in an internal chamber surrounding the evaporator and having an aperture opening on the same side of the substrate; generating a vapor; b) introducing a reactive gas into the internal chamber; C) directing the metal vapor and reactive gas through an aperture toward the substrate; and d) directing an electron beam into the internal chamber. and e) select an accelerating voltage of at least 2 CI KV and interact for ionization purposes with the negative charge carriers formed in the internal chamber or blocked in the chamber opposite the aperture. Solved by suction through the diaphragm opening by means of an electrode located outside the vapor stream and positively biased with respect to earth, creating a glow discharge that burns violently in the area of the diaphragm opening and the electrode. be done.

Effect (1) In the method according to the invention, all features a) to e) are integral and mutually necessary.

By damming at least a portion of the vapor and the reaction gas and also the reaction products consisting of the metal vapor and the reaction gas in the inner chamber, a significantly higher ionization is generated in conjunction with the electron beam confined within the inner chamber, and the ionization can be considered to be a numerical comparison of another zushi. higher than the state of the art, more than 20 KV, advantageously about 60-40
Due to the acceleration voltage of the KV electron beam, it is extremely powerful.
A magneton beam is generated which is not deflected by the magnetic field of the anode current and therefore remains stable. As a result of the suction of negative charge carriers by the constriction that constricts the vapor and gas flows, the ionization probability is increased again in the region of the constriction and the electrode. In the method carried out with the operating parameters described in more detail below, a white, blazing, visible and intensely luminescent plasma was generated as described above, which also produced a large amount of supplied gas. The desired complete reaction with metal vapor was also possible. Although it was possible to achieve a deposition rate of 5.0 μm/m 1 n as is in this format, the end of the increasing potential was still not discerned.

Due to the positively biased t-body being located outside the vapor flow, the vapor flow does not impinge on it, at least not directly, and for this reason also its operational performance deteriorates over long periods of time. )! will be taken away. ``The condition of the outside of the steam flow is actually that when viewed from the projection drawing, the steam flow does not fit within the class 9 opening, and at most it coincides with the edge of the diaphragm/opening. The knee is placed in the shape of 164 feet.

In this case, it is advantageous for the inner chamber and the steam chamber to be placed at the same potential, preferably at ground potential. This takes place, for example, by an electrically conductive metallic connection between the two components.

Furthermore, the electrode opposite the aperture has +5 to +10 DV.
, advantageously a bias of +20 to +40 V is applied.

Since the substrate can in principle also be held at ground potential, it is advantageous to apply a voltage of -50 to -2000 m to the substrate, whereby a type of ion implantation of positive charge carriers is achieved. be done.

Problem to be Solved by the Invention (Part 2) Another problem to be solved by the present invention is an apparatus for carrying out the method, which comprises an external vacuum chamber, an evaporation crucible, and an evaporation material present in the evaporation crucible. The object was to provide a type having an electron gun for shooting together with the electron beam and an electrode which is arranged between the evaporation crucible and the substrate and which can be applied to a positive potential with respect to ground.

Means for Solving the Problem (Part 2) The problem is that in the above type of apparatus for reactive vapor deposition on a substrate, a) the space above the evaporation crucible is surrounded by an internal chamber, and the internal chamber is an entrance aperture for the beam and a diaphragm aperture arranged in the direction of the substrate, b) the internal chamber is provided with a supply mechanism for a reactive gas, and c) opposite the diaphragm aperture a projection plane of the diaphragm aperture. The solution is that the electrodes which are not present are arranged in an insulated manner and are connected to a DC voltage source with a positive output voltage with respect to ground.

In this case, the internal chamber is configured in the shape of a rectangular parallelepiped, and the open lower side supports the evaporation crucible.
One of the two upright side walls has an entrance aperture for the electron beam, a diaphragm aperture is arranged in the upper horizontal wall of the inner chamber, and an electrode is fixed separately on the upper horizontal wall. It is particularly advantageous to have

According to the configuration described above, a very compact structure is obtained in which the internal chamber simultaneously serves as a support for the electrode relative to the substrate.

Owing to the high discharge efficiency, particularly in the area of the diaphragm opening and the electrode, it is particularly advantageous for the frame-shaped electrode to have cooling channels.

Furthermore, the polar planes of the deflection magnet system are arranged on both sides of the internal chamber, and the electron beam travels within the plane of symmetry between the two polar planes at least at the central position! It is advantageous that the

A "central position" of an electron beam is to be understood as a position equidistantly spaced apart from both end positions of a periodically or oscillally deflected electron beam. In order to be able to cover a larger area with evaporates,
It is particularly advantageous to vibrate the electron beam.

Example The invention will now be described in detail with reference to the illustrated embodiments.

FIG. 1 shows a vacuum chamber 1 which is evacuated via a suction connection 2 by a pump unit (not shown). An internal chamber 3 is provided within the external vacuum chamber 1;
The internal chamber has a horizontal bottom 4, four vertical side walls 5 and an upper wall 6 which is again horizontal. An evaporation crucible 7 is placed on the bottom 4 , in which a molten liquid evaporator 8 is placed and surrounded by a cooling coil 9 .

In the left-hand side wall 5 an entrance aperture 10 is provided for an electron beam 11 which is deflected onto the surface of the evaporator 8 in an arcuate trajectory.

The beam deflection means will be explained in detail with reference to FIG. An electron gun 12 with a deflection system 13 is installed behind the entrance aperture 10, which deflects the electron beam 11 periodically toward the surface of the evaporator 8 based on a predetermined deflection pattern controlled by a program generator. be biased towards

The upper wall 6 is configured as a diaphragm, ie has a diaphragm opening 14, which has a compensating cross-section that is significantly smaller than the total cross-sectional area of the interior chamber 3. In the lower part of the internal chamber 3 a feed mechanism 15 is provided, which consists of two perforated straight tubes extending perpendicular to the drawing and serving as a reservoir for feeding the reaction gas.

The vapor of the evaporator 8 formed by the action of the electron beam 11 and the gas supplied via the supply mechanism 15 are passed through the aperture 1
4 and is guided to a substrate 16 which is placed stationary or movably above the diaphragm aperture 14. In this case,
Substrate 16 is shown in a stationary state.

Opposite the aperture aperture 14, that is, the upper wall 6 and the substrate 16
An electrode 1 that does not exist in the projection plane of the diaphragm aperture 14 and is supported on the upper wall 6 with an insulator 18 interposed therebetween.
7 is provided. The inner edge 14a of the diaphragm opening 14 forms a rectangle. This means that the inner edge 17a of the electrode 17
The edges also form a rectangular frame. In this case, the inner edges 14a and 17a should be arranged substantially co-linear with each other, but slight deviations from the co-linear position are of course not a problem.

The electrode 17 is surrounded at its outer edge by a cooling channel 19 serving for the flow of cooling water.

The inner chamber 3 is earthed like the outer vacuum chamber 1 and the evaporation crucible 7, while the electrode 17 is connected to the conductor 20 and the insulated guide 2.
1 to a voltage source 22, which applies a positive potential to the electrode 17 with respect to ground. It is likewise possible for the substrate 16 to be at ground potential, but as shown in FIG. Said potential difference between the electrode 17 and the internal chamber 3 in the region of the diaphragm opening 14 results in a very intense glow discharge, the upper and lateral boundaries of which can be approximately indicated by the dashed lines 26. .

For example, the distance between the upper side of the upper wall 6 and the upper side of the electrode 17 is 31+m, and the distance between the upper side of the electrode 17 and the lower side of the substrate 16 is 64 m.

In FIG. 2, the same parts or parts having the same function as in FIG. 1 are given the same reference numerals.

Additionally, the following is shown:

A number of substrates 16 are fixed in a movable substrate holder 27 that is movable in a direction perpendicular to the drawing by means of rollers and rail guides 28 . A drive motor 29, a pinion 30 and a rack 31 serve for the drive (periodic reciprocating movement). On the opposite side of the substrate holder 27 is a roller 32
It is supported by the traveling rail 33 via. On the substrate 16, a heating mechanism 34 for heating the substrate 16, a heat insulation mechanism 35, and a heating current supply and (
A cable traction mechanism 36 is provided for applying a negative bias to the substrate 16 (if desired).

Furthermore, the internal chamber includes a bracket 3 in the lower part of the vacuum chamber 1.
It can be seen that it has a downwardly open bottom 37 supported at 8. Immediately below or in the bottom 37 is an evaporation crucible 7.

On both sides of the internal chamber 3 there are pole faces 39, partially indicated in dashed lines, which are formed from the inside of the legs of the U-shaped deflection magnet system 40O. Both legs are connected to each other by a yoke 41, which includes, although not shown here,
There is a magnetic coil. By means of the deflection magnet system, the electron beam 11 is deflected into the curved trajectory illustrated in FIGS. 1 and 2 and is intentionally directed towards the evaporator 8.

FIG. 2 also shows a second supply mechanism 42 for another reactant gas, if desired.

FIG. 3 shows a top view of an electrode 17 made of copper, surrounded on three sides by cooling channels 19. Contact screws 43 serve for connection of the current supply. The effective dimensions of the electrodes 17 given by the spacing of the inner edges 17a of each pair running parallel to each other are 90.times.135 mm.sup.2. 3 is self-explanatory if it is assumed that the substrate 27 and all other components shown in FIG. 2 are omitted.

FIG. 4 shows a plan view of the evaporation crucible 7 containing the evaporated material 8. Supply mechanism 1 for the reaction gas consisting of perforated tube sections on both sides of the crucible opening defined by the inner edge 7a
5 is extended.

FIG. 4 is self-explanatory if the internal chamber 3 and all components thereon are removed.

EXAMPLE 1 In an apparatus with a unit according to FIGS. 2 to 4, a sheet metal strip of special steel was arranged as substrate 16. The evaporate consisted of titanium. The pressure inside the external vacuum chamber 1 is nitrogen (N
2) was adjusted to approximately 10 −2 mbar by metering.

The reactive evaporation process was started by a shot of the evaporator 8 with an electron beam 11 with an accelerating voltage of 35 KV and a beam current of 1.7 A. The voltage at electrode 17 was +30 V, in which case an anodic current of 20 OA was generated at the electrode. The negative bias of the substrate was -ioov. The treatment continued for 50 seconds by moving the substrate back and forth several times. The coverage calculated from this was 5.0 μm7'min. The golden layer applied is HV = 1200 KP/mrtr2
In addition to its hardness, it also had sufficient adhesion strength so that it could not be peeled off even when the special steel elbow board was bent at an acute angle.

Scanning electron micrographs show that the coating layer is extremely dense and exhibits tuft-like growth (Stengelwax), which is different from the experimental results as observed in methods according to the state of the art.
hstum).

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing the principle structure of the device according to the present invention, FIG. 2 is a vertical sectional view of the actually constructed device, and FIG.
4 is a plan view of the lower part of the interior chamber, in which the supply device for the reaction gas is arranged; FIG. 3...Inner chamber, 5...Vertical side wall, 6...Upper horizontal wall, 7...Evaporation crucible, 10...Incidence opening, 11...
- Electron beam, 14... Aperture aperture, 14a... Inner edge of aperture aperture, 15... Supply mechanism, 16... Substrate, 17... Electrode, 17a... Inner edge, 19 ...
Cooling passage, 22... DC voltage source, 39... Pole surface, 4
0... Deflection magnet system 3... Internal chamber 7... Evaporation crucible 10... Incidence aperture 11 - Electron beam 16 Substrate 17 Electrode 22 - Current voltage source 3 Internal chamber I Evaporation crucible 14 - Aperture aperture 15 - Supply mechanism 16 board

Claims (1)

[Claims] 1. A pressure of up to 10-1 mbar in an atmosphere consisting of a reactive gas, in the form of an electrode positively biased with respect to earth in the range of the vapor flow towards the substrate; A method for reactively depositing a metal compound onto a substrate by evaporating at least one metal using an electron beam in a process comprising: a) depositing the metal vapor in an interior chamber surrounding the evaporator and having an aperture opening opposite the substrate; b) introducing a reactive gas into the internal chamber; c) directing the metal vapor and reactive gas through an aperture toward the substrate; and d) ionizing the electron beam with the metal vapor and reactive gas within the internal chamber. select an accelerating voltage of at least 20 KV, and e) transfer the negative charge carriers formed in the internal chamber or sequestered therein to the opposite side of the aperture opening and outside the vapor flow; substrate, characterized in that it attracts suction through the diaphragm aperture by means of an electrode located and positively biased with respect to ground, thereby generating a glow discharge that burns violently in the region of the diaphragm aperture and the electrode. method of reactive vapor deposition. 2. Add +5 to +100 to the electrode located opposite the aperture aperture.
2. The method of claim 1, wherein a bias of V is applied. 3. The method according to claim 1, wherein a voltage of -50 to -2000V is applied to the substrate. 4. Using an electron beam at a pressure of up to 10-1 mbar in an atmosphere consisting of a reactive gas, with an electrode positively biased with respect to earth placed within the range of the vapor flow towards the substrate. An apparatus for carrying out a method for reactively depositing a metal compound onto a substrate by vaporizing at least one metal, the apparatus comprising: an external vacuum chamber; an evaporation crucible; of the type comprising an electron gun for shooting together and an electrode placed between the evaporation crucible and the substrate and capable of applying a positive potential with respect to earth, a) on the evaporation crucible (7); The space is surrounded by an internal chamber (3), which internal chamber has an entrance aperture (10) for the electron beam (11) and a diaphragm aperture (14) arranged in the direction of the substrate (16). b) the internal chamber (3) is equipped with a reactive gas supply mechanism (15), and c) opposite the aperture aperture (14) an electrode ( 17) is arranged in an insulated manner and the electrode is connected to a DC voltage source (22) having a positive output voltage with respect to ground. 5. The internal chamber (3) is configured in the shape of a rectangular parallelepiped, and its open lower side supports the evaporation crucible (7), and one of the four upright side walls of the internal chamber is configured to support the electron beam (11). a diaphragm aperture (14) arranged in the upper horizontal wall (6) of the inner chamber, and a separate electrode on the upper horizontal wall (6). 5. The device according to claim 4, wherein (17) is fixed. 6. The aperture aperture (14) is configured in a rectangular shape and the electrode (17)
) is configured as a rectangular frame, and the inner edge (17a) of the frame is the inner edge (17a) of the aperture aperture (14).
14. The device of claim 5, wherein the device is substantially collinear with 14a). 7. Device according to claim 6, in which the frame-shaped electrode (17) has cooling channels (19). 8. On both sides of the internal chamber (3) are the polar faces (
5. The device according to claim 4, wherein a polar plane (39) is arranged and the electron beam travels in a plane of symmetry between the two polar planes (39) at least in its central position.